Sewage effluent discharge and geothermal input in a natural wetland, Tongariro Delta, New Zealand

Wetland nutrient removal: a review of the evidence

“…While wetlands may act to reduce the eutrophication of adjacent ecosystems, they may become eutrophic themselves. Increased weed invasion (Chague-Goff et al, 1999) and reduced plant diversity (Osborne and Totome, 1994) have been reported. There has also been a paucity of studies to assess the effectiveness of long term nutrient reductions and the ecological effects on the wetland of receiving such nutrient loadings.…”

“…Hence, it is important to review the effectiveness of wetlands in improving water quality, particularly because of a number of concerns regarding the use of wetlands to reduce nutrient loadings. For example, it has been found that wetlands used to reduce nutrient loadings may become degraded (Osborne and Totome, 1994;Chague-Goff et al, 1999) and incomplete denitrification may release the greenhouse and ozone depleting gas, nitrous oxide (Machefert et al, 2002). These issues are particularly topical given the use of wetlands as an important element in river basin management strategies, for instance, within the River Danube and River Tisza catchments.…”

Natural wetland restoration and the use of municipal wastewater

“…Only few studies have discussed the removal of heavy metals in wetlands (Chagué-Goff et al, 1999;Sobolewski, 1996;Vymazal, 2003Vymazal, , 2005 because heavy metals do not constitute a major problem in municipal wastewater. Whereas Fe, Cu, and Mn were mostly provided by wastewater, tap water for groundwater simulation contained more Zn than wastewater which could be attributed to domestic piping.…”

Arsenic in Natural Environments

“…Swamps, marshes, bogs, sloughs, and fens are examples of wetlands. Like other surface environments, arsenic in wetland water, sediments, and soils (including peats) may originate from a variety of sources, including seawater (Dellwig et al, 2002), natural weathering, mining wastes, pesticide runoff, the leaching of chromated copper arsenate (CCA)-treated wood ( (Cobb et al, 2006); Chapter 5), geothermal waters (Chagué-Goff, Rosen and Eser, 1999), groundwater , and air emissions from coal combustion facilities ( (Graney and Eriksen, 2004;Shotyk et al, 2003); Tables 3.11 and 3.12). Peats and other wetland soils often contain a variety of organoarsenicals, including methylarsenic, arsenobetaine ((CH 3 ) 3 As + CH 2 CO 2 − ), arsenocholine ((CH 3 ) 3 As + CH 2 CH 2 OH), and arsenosugars, all of which result from biological activity (Huang and Matzner, 2006).…”